An underwater glider is a type of autonomous unmanned underwater vehicle (“AUV”) that is powered by a buoyancy engine. The buoyancy engine is carried by the glider and typically includes a motor that is operative for changing the effective volume of a chamber, so that the chamber alternately ingests and expels ambient water to change the mass of the glider, so that the glider alternately ascends and descends. Conventional gliders typically include hydrodynamic wings for causing the AUV to move forward while alternately descending and ascending in the water. A conventional underwater glider with a conventional buoyancy engine may be inadequate in some situations.